Our invention concerns apparatuses for positioning a patient's head when imaging tissue or bones in the region of the patient's neck and spine. One method of imaging is a myelographic examination wherein a patient lies prone with his head held tilted by a head support stand. The myelographic examination requires that a contrasting or image enhancing agent be introduced in the area being examined. The introduction is done by injection through a a needle placed approximately two millimeters from the patient's spinal cord. After placement of the needle, the patient's head is repositioned until the bones of the spinal column are properly aligned for imaging. Movement of the head is accomplished via trial-and-error resetting of the head support stand. This movement, unless smooth and well controlled, can cause loss of myelogrphic test data, pain to the patient, and injury to the spinal column by the needle.
A current head support stand is disclosed in U.S. Pat. No. 4,504,050 to Osborne, wherein a repositionable face plate is mounted between two uprights. The face plate is moved after loosening knobs on the uprights near the plate's temple area or after loosening other knobs near the plate's chin area. Movement of the face plate is done by hand, whereby the accuracy and smoothness of the movement are limited.
Other head support stands are shown in U.S. Pat. Nos. 3,957,262 3,319,954 and 2,507,172. Given the dates of these references, we believe the problems with control and smoothness in head stand repositioning have remained unrecognized and unsolved for at least twenty-five years.